Will Smith plays an interplanetary ranger in M. Night Shyamalan’s dreary “After Earth,” which is set a thousand years in the future, although it all seemed too drearily present-day to me. The gimmick here is that Smith’s son is played by Jaden Smith, his actual son.

Smith’s ranger is a martinet ranger whose cadet son desperately wants to live up to his father’s impossibly high standards. He gets the chance when their spaceship crash-lands on the planet Earth, which humans were forced to evacuate a thousand years earlier due to a global cataclysm. The boy, in order to rescue his dad and himself – the vessel’s sole survivors – faces off against everything from neo-condors to gloppy monsters. (Not withstanding the movie's misleading ads, Jaden has far more screen time than Will.)

But his fiercest adversary is the screenplay. Replete with howlers, it had the audience I saw the film with in titters from very early on. Jaden Smith was a good little actor in “The Pursuit of Happyness,” in which he also costarred, to much better effect, with his father. Will Smith’s patriarch never cracks a smile. That’s how you know he’s serious. But it’s impossible to take this movie seriously, certainly not as seriously as it takes itself. Grade: C- (Rated PG-13 for sci-fi action violence and some disturbing images.)